# Caustic Ingestions, Button Batteries, and Foreign Body Toxicology

## Caustic Ingestions

### Overview

Caustic substances include acids with a pH below 2 and alkalis with a pH above 12. Most caustic ingestions occur in children between ages 1 and 5 (accidental) and in adults (intentional). Common alkali agents include drain cleaner (sodium hydroxide), oven cleaner, bleach (usually low concentration), ammonia, and dishwasher pods. Common acid agents include toilet bowl cleaner, battery acid (sulfuric acid), hydrochloric acid, and rust removers.

### Alkali vs. Acid Injury

Alkali injuries are generally more dangerous than acid injuries. Alkalis cause liquefactive necrosis, which saponifies fat and denatures proteins, allowing deep tissue penetration. The injury is progressive and continues to penetrate until the alkali is neutralized or diluted. Alkali primarily affects the esophagus because it traverses the stomach quickly, and it carries a higher risk of perforation, mediastinitis, and long-term stricture formation.

Acids cause coagulative necrosis, in which protein denaturation creates a protective eschar that limits the depth of injury. Acid primarily affects the stomach because pyloroduodenal spasm causes the acid to pool there. The exception is hydrofluoric acid, which causes a penetrating injury pattern.

### Clinical Presentation

Patients present with oral burns, drooling, dysphagia, odynophagia, chest pain, and abdominal pain. Stridor and hoarseness indicate laryngeal edema. Vomiting, sometimes bloody, may occur. An important clinical principle is that the absence of oropharyngeal burns does not exclude esophageal injury — up to 30 percent of patients without visible oral burns have significant esophageal injury.

### Management

Airway assessment should be performed early. If stridor, hoarseness, or respiratory distress is present, early intubation is indicated because edema can progress rapidly. Vomiting should not be induced, as it re-exposes the esophagus to the caustic substance. Neutralization should not be attempted because the exothermic reaction can worsen the injury. A nasogastric tube should not be placed blindly due to the risk of perforation. Small sips of water or milk for dilution in the immediate period are acceptable and unlikely to cause harm, though this practice is controversial. The patient should be kept NPO pending endoscopy. IV fluid resuscitation and pain management should be initiated. Antibiotics and steroids are not routinely recommended; steroids do not prevent stricture formation and may mask signs of perforation.

### Imaging

Chest and abdominal radiographs should be obtained to evaluate for pneumomediastinum, pneumoperitoneum (indicating perforation), and pleural effusion. CT of the chest and abdomen with IV contrast is increasingly used to grade the injury and identify perforation, and it may help determine whether surgery or endoscopy is needed.

### Endoscopy

Endoscopy should be performed within 12 to 24 hours of ingestion, but it should be avoided between days 5 and 15 post-ingestion because tissue weakness peaks during this window and the risk of perforation is highest. The Zargar classification grades the injury: Grade 0 is normal, Grade 1 shows edema and erythema, Grade 2a shows superficial ulceration with friability and exudates, Grade 2b shows deep or circumferential ulceration, Grade 3a shows focal necrosis, and Grade 3b shows extensive necrosis. Grades 2b and 3 carry a high risk of stricture formation and perforation. The endoscope should not be advanced beyond a circumferential Grade 3 lesion.

| Zargar Grade | Endoscopic Findings | Stricture Risk | Management |
|-------------|--------------------|----|------------|
| 0 | Normal | None | Discharge |
| 1 | Edema, erythema | Minimal | Observe, advance diet |
| 2a | Superficial ulceration, friability | Low | Observe, NPO then advance |
| 2b | Deep or circumferential ulceration | High | ICU, NPO, serial imaging |
| 3a | Focal necrosis | Very high | Surgical consultation |
| 3b | Extensive necrosis | Very high | Likely surgical intervention |

### Complications

Acute complications include perforation, mediastinitis, peritonitis, and airway compromise. Subacute complications include infection and fistula formation. Chronic complications include esophageal stricture developing over weeks to months and a 1000-fold increased risk of esophageal squamous cell carcinoma, with a latency period of 15 to 40 years.

## Button Battery Ingestion

### Epidemiology and Mechanism

Lithium coin cell batteries, especially the 20 mm CR2032, cause the most severe injuries. The mechanism is electrochemical: the battery generates an external current that hydrolyzes tissue fluid, creating hydroxide ions (alkali) at the negative pole. Injury begins within 15 minutes of mucosal contact and can cause full-thickness necrosis within 2 hours. The most dangerous location is the esophagus, where erosion into the aorta can create an aortoesophageal fistula with fatal hemorrhage.

### Clinical Presentation

Patients may be asymptomatic initially. Symptoms include dysphagia, drooling, vomiting, chest pain, and refusal to eat. Hematemesis is ominous and may indicate vascular erosion. The presentation is often mistaken for croup, upper respiratory infection, or a non-battery foreign body. Because unwitnessed ingestion is common, a high index of suspicion is needed in young children.

### Imaging

AP and lateral X-rays of the chest and abdomen should be obtained. A button battery appears as a round density with a "double halo" or "step-off" sign on lateral view, which distinguishes it from a coin. The key determination is whether the battery is in the esophagus, the stomach, or beyond the pylorus.

### Management

A button battery in the esophagus is an emergent time-critical situation requiring endoscopic removal within 2 hours. ENT, GI, or surgery should be contacted immediately. While awaiting endoscopy, honey (10 mL every 10 minutes in children older than 12 months) or sucralfate may reduce injury by creating a protective barrier; this is a newer recommendation supported by animal data and National Capital Poison Center guidance. Honey must not be given to infants under 12 months because of the risk of botulism.

A gastric button battery in an asymptomatic patient, if the battery diameter is less than 20 mm, can be observed with a repeat X-ray at 48 hours. If the battery is larger than 20 mm or symptoms are present, removal should be considered. A battery beyond the pylorus usually passes spontaneously and can be followed with serial X-rays, with removal indicated if it fails to progress within 48 to 72 hours or symptoms develop. After removal, patients must be monitored for delayed complications including stricture, perforation, and fistula, which may present days to weeks later.

### Catastrophic Complications

Catastrophic complications include aortoesophageal fistula with massive hemorrhage (often preceded by a sentinel bleed before exsanguination), tracheoesophageal fistula, esophageal perforation with mediastinitis, vocal cord paralysis from recurrent laryngeal nerve injury, and death, which has been reported even when batteries were removed within hours.

## Magnet Ingestion

### Mechanism of Injury

A single magnet is generally benign and passes without complication. Multiple magnets, or a magnet combined with a metallic object, are far more dangerous because magnets attract each other across bowel loops, causing pressure necrosis that leads to perforation, fistula formation, volvulus, and obstruction. High-powered rare-earth (neodymium) magnets are particularly dangerous.

### Management

X-ray should be obtained to determine the number and location of magnets. A single magnet beyond the esophagus can be observed with serial X-rays. Multiple magnets require endoscopic removal if accessible in the stomach or proximal duodenum, and surgical removal if they are beyond endoscopic reach and the patient is symptomatic or the magnets are failing to progress. Patients who have ingested multiple magnets should be admitted for observation even if asymptomatic.

## Other Foreign Bodies

### Coins

Coins are the most common foreign body ingested by children. Esophageal coins should be removed within 24 hours if symptomatic or located at the cricopharyngeus, though asymptomatic coins at the lower esophagus may be observed for up to 24 hours. Gastric coins typically pass spontaneously, with a follow-up X-ray in 2 to 4 weeks if not passed.

### Sharp Objects

Sharp objects such as pins, needles, toothpicks, bones, and razor blades in the esophagus require emergent endoscopic removal. In the stomach, endoscopic removal is indicated if the object is longer than 6 cm, wider than 2.5 cm, or sharp. Beyond the pylorus, serial X-rays are obtained with surgical removal if the object fails to progress or symptoms develop. Open safety pins in the esophagus or stomach should be removed endoscopically with the pin trailing.

### Food Bolus Impaction

Food bolus impaction typically occurs in patients with underlying esophageal pathology such as eosinophilic esophagitis, stricture, or Schatzki ring. Glucagon 1 mg IV may be tried first, though its efficacy is controversial. If conservative measures fail, endoscopic removal is performed. Complete obstruction where the patient cannot handle secretions requires emergent endoscopy. Carbonated beverages have some evidence supporting their use, as CO2 generation may dislodge the bolus.

### Body Packing and Body Stuffing

Body packers are individuals who have professionally wrapped drug packets for smuggling; these are well-wrapped and have a lower rupture risk. Body stuffers have hastily swallowed drugs to avoid arrest; their packets are poorly wrapped with a higher rupture risk. CT is more sensitive than X-ray for detection, with packets appearing as well-defined radio-dense objects. Asymptomatic body packers are managed with whole bowel irrigation until all packets pass, confirmed by serial X-rays. Symptomatic patients with packet rupture require aggressive resuscitation, specific antidotes (naloxone for opioids), and surgical removal. Endoscopic removal of drug packets should never be attempted because of the risk of rupture.

<image>A two-panel X-ray comparison of button battery versus coin in the esophagus. Panel 1: AP view showing a round radio-dense object in the upper esophagus — button battery appearing as a round density with a subtle double ring (double halo sign). Lateral view showing a step-off at the junction of the anode and cathode. Panel 2: AP view showing a coin in the esophagus — uniform round density without double ring. Lateral view showing a thin, uniform disk without step-off. Annotations highlight the distinguishing features and emphasize that the step-off on lateral view is the key to identifying a button battery versus a coin.</image>

<image>A diagram of the esophagus showing the mechanisms and locations of button battery injury. The esophagus is shown with three natural narrowing points (cricopharyngeus, aortic arch/left mainstem bronchus crossing, and lower esophageal sphincter) where batteries are most likely to lodge. An inset shows the electrochemical mechanism: the battery's negative pole generates hydroxide ions through electrolysis, creating an alkaline burn. Adjacent structures at risk are labeled: trachea (tracheoesophageal fistula), aorta (aortoesophageal fistula with hemorrhage risk), and recurrent laryngeal nerve (vocal cord paralysis). A timeline shows: injury begins within 15 minutes, significant mucosal damage by 30 minutes, full-thickness necrosis possible within 2 hours.</image>

<image>A management algorithm for foreign body ingestion. Starting with "Foreign body ingested" branching by type: Button battery → location? Esophageal = emergent removal within 2 hours (give honey q10 min if child older than 12 months while awaiting endoscopy); Gastric/beyond = observe if small and asymptomatic, remove if large or symptomatic. Sharp object → Esophageal = emergent removal; Gastric = remove endoscopically; Beyond pylorus = serial X-rays, surgery if fails to progress. Multiple magnets → accessible = endoscopic removal; beyond reach = surgical consultation, admit for observation. Coin → Esophageal = removal within 24 hours; Gastric = observe, follow-up X-ray in 2-4 weeks. Drug packet → asymptomatic = WBI until passage; symptomatic = resuscitation + antidotes + surgery (no endoscopy).</image>

## Clinical Pearls

The absence of oropharyngeal burns does not exclude esophageal injury in caustic ingestion, as up to 30 percent of patients have significant esophageal burns without visible oral lesions. Vomiting should not be induced, neutralization should not be attempted, and a nasogastric tube should not be placed blindly in a caustic ingestion. Alkali injuries are generally worse than acid injuries because liquefactive necrosis allows deep penetration. A button battery in the esophagus is a time-critical emergency in which tissue injury begins within 15 minutes and removal should occur within 2 hours. On X-ray, the step-off sign on lateral view distinguishes a button battery from a coin, and this distinction is critical. Honey at 10 mL every 10 minutes (for children older than 12 months) given before endoscopy may reduce button battery injury and is an emerging recommendation from the National Capital Poison Center. Multiple magnets are far more dangerous than a single magnet because they attract across bowel loops, causing pressure necrosis and perforation. Drug packets should never be removed endoscopically because the risk of rupture is too high.

## References

- Lupa M, et al. Update on the diagnosis and treatment of caustic ingestion. *Ochsner J*. 2009;9:54-59.
- Anfang RR, et al. pH-neutralizing esophageal irrigations as a novel mitigation strategy for button battery injury. *Laryngoscope*. 2019;129:49-57.
- Kramer RE, et al. Management of ingested foreign bodies in children: a clinical report of the NASPGHAN Endoscopy Committee. *JPGN*. 2015;60:562-574.
- National Capital Poison Center. Button battery ingestion triage and treatment guideline. 2023.
- ASGE Standards of Practice Committee. Management of ingested foreign bodies and food impactions. *Gastrointest Endosc*. 2011;73:1085-1091.